Process of stuffer-crimping lubricated synthetic fibers



ilnite 3,432,898 PRUCEEYS OF STUFFER-CRIMPING LUBRICATED SYNTHETIC FEBERS Robert K. Stanley, Media, and Hillary Robinette, In,

Philadelphia, Pa, assignors to Techniservice Corporation, Kennett Square, Pa. No Drawing. Filed Mar. 19, 1965', Ser. No. 441,341 US. Cl. 2%72 13 Claims Int. Cl. Dil ih 13/00 ABSTRACT F THE DISCLOSURE The invention deals with the treatment of fibers specifically, the invention concerns lubricated fibers which have a coating of a fatty acid ester or ether which is stable against decomposition at elevated temperatures. The invention also provides a process for treating a fiber with such a fatty acid derivative. The treated fiber is ideally suited for crimping, particularly crimping by compressive methods such as by the stutter-crimping method.

In accordance with known methods, man-made fibers are generally impregnated with a textile finishing composition for imparting softness, lubricity, antistatic, and like properties to the fibers, or filaments, to facilitate processing of the fibers in subsequent operations as spinning, twisting, winding, reeling, warping, carding, drafting, weaving and crimping and other operations. Such conventional finishing agents may be glycerine, lauryl alcohol, sorbitan monopalmitate, butyl oleate and others.

Many such processing operations require that the fiber be exposed to heat. Under elevated temperatures the finish may be degraded, decomposed, polymerized, or in one way or the other removed so that it becomes ineffective to give the fiber the required properties, in particular lubricity, required in further operations. In processing involving crimping, especially compressive or stuttercrimping of fibers, this problem has become especially acute. In stutter-crimping, extreme conditions of friction occur. Since the fibers are curled up, folded, compressed and crimped on themselves an innumerable number of times within the confines of a chamber under elevated temperature conditions while continuously under a pressure which moves the fibers, the fibers must be slideable with respect to other fibers with which they come into frictional relationship and also with respect to the inside walls of the metal stuifing-chamber. These are extremely severe conditions for which no exact counterpart is found in other processing or treatment of fibers.

In the course of the crimping operation, conventional lubricants, or finishes on the fibers degrade imperceptibly during their treatment, often forming what appears to be a sticky, sludge-like invisible film, so that the operations become uneven, are slowed and may break down, as slideability of the fibers is reduced and excess friction develops. Moreover, later during drying of the fibers further problems may arise from the degradation of the lubricant. The shortcomings of conventional finishes or lubricants therefore cause serious problems in their processing.

The fiber lubricant of the present invention largely overcomes these problems. The lubricant imparts to the fiber excellent lubricity with respect to other surfaces, such as other fibers, metal surfaces, glass, ceramics, synthetic materials or others. The fiber, coated or impregnated with the lubricant of the invention, retains its lubricity at elevated temperatures, such as over 400 F. The fiber is ideally suited for crimping, particularly stutter-crimping. The fibers retain their slideability with respect to adjacent fibers and metal surfaces such as the walls of the stutter-box or chamber with which the fiber is in contact. These necessary properties are retained notwithstanding the extreme compactness of the fibers and the pressure prevailing in the confines of the chamber, as well as the prevailing elevated temperatures. These temperatures may range up to the melting point of the fiber, generally in the range of about 300 to about 400 or about 450 F., for a time sufficient to crimp the fiber, as for instance for about 2 to 10 minutes, generally for about 3 to 5 minutes.

To impart these properties to the fibers according to one embodiment of this invention, the fiber is treated with a specific fatty acid ester. Esters useful in the practice of the invention include the esters of monohydric and polyhydric alcohols and saturated fatty acids having a total carbon atom content of about 22. The fatty acid may have a carbon atom content of 8 to 24; particularly 12 to 22 carbon atom acids are most suitable. Typical are the following: caprylic, capric, lauric, myristic, palmitic, stearic, arachidic, behenic and the like. The esters are those of monohydric and polyhydric alcohols typified by the following: mono-, di-, and tri-substituted carbinols, such as ethyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-octyl, iso-octyl, Z-ethylhexyl, octadecyl, lauryl, cyclohexyl, and benzyl alcohols; polyhydric alcohols such as ethylene glycol, 1,2-propylene glycol, Z-ethylhexanediol- 1,3, butanediol-LZ, dodecanediol-1,12; diand tri-ethylene glycols; glycerol; pentaerythritol; and the isomers and homologues of the above. A particular useful group of esters are those of saturated fatty acids of 16 to 2'2 carbon atoms and alkanols, especially highly branched mixtures of isomeric alkanols having at least 6 carbon atoms, such as isohexyl-, isooctyl-, isodecyl, 4,5-dimethy1- l-hexanol, S-methyl-l-heptanol, 4-methyl-1-pentanol, and the like, such as are obtained from the 0x0, the synthol, or oxyl processes.

Also useful likewise, according to another embodiment of the invention, are the corresponding ethers of these fatty acids in which the alkoxy group has the same definition as the alkyl group where the invention is discussed hereinafter with reference to esters it will be understood that the same discussion would apply to the corresponding ethers without necessity for repetition to that effect.

A particular useful lubricant is isooctyl .palmitate. Another is butoxy ethyl stearate.

Mixtures of esters are useful too, both the esters of mixtures of the alcohols and/ or of the acids and of both. It is desirable that the esters be water-soluble in the bath in which the fiber is treated or at least dispersible therein.

In accordance with the first embodiment of the invention, the fiber is impregnated with the lubricant by passing it through a bath comprising a volatile carrier 'for the fatty acid ester. Preferably, the volatile carrier is water. The amount of fatty acid ester lubricant in the bath varies in accordance with the extent of lubricity required of the fiber, the type of fiber, the nature of the material from which the fiber is made, the length of treatment and other factors. Satisfactory results are obtainable with an amount of 2 to 10% preferably 4 to 8%. by weight of ester in the bath. Generally, the ester is dissolved in the water, or it may be dispersed therein. The fiber is passed through the bath in such a manner as to coat, or impregnate, the fiber with the ester. The pick-up of liquid by the fiber may range from 10 to 30%. Generally, the wet treated fiber upon removal from the bath may have an amount of 0.4% to 2.0%, more often 0.8% to 1.6% by weight of ester retained on the fiber. The application of the ester to the fiber may be promoted by heating the treating bath at a temperature in the range of about 120 F. to the boiling temperature of the bath, generally 120 to 140 F. being quite satisfactory.

The impregnation of the fiber with the ester can be promoted by using an inert wetting or surface active dispersing agent. The dispersing agent which is suitable for use in the process includes those of the non-ionic, anionic and cationic groups. The preferred dispersing agents are of the non-ionic type, especially the condensation products of ethylene oxide with a hydrophobic organic material such as a long chain aliphatic alcohol, acid, ester, ether or an alkyl phenol. These products are characterized by containing as the hydrophilic portion of the molecule a plurality of oxyethylene moieties, as in the formula given below, RO(CH CH O) CH OH wherein R is an alkyl group having from 12 to 22 carbon atoms or an alkyl phenol residue wherein the alkyl group contains from 6 to 13 carbon atoms inclusive and wherein x is at least 4 especially between about 6 and about 40. The ethylene oxide residues may vary considerably as from to 90 mole percent, especially to 20 mole percent. Commercial examples of products in this group include Triton X-l00 wherein R is an alkyl phenol residue, wherein the alkyl group is isooctyl and wherein x is 7 to 9; Triton X-102 wherein R is an isooctyl phenol residue and x is 11; Tergitol NPX wherein R is ethylhexyl phenol residue and x is 8 to 0; Neutronic 600 wherein R is nonyl phenol residue and x is 9; Emulphor ELN wherein R is dodecyl phenol residue and x is 19. Also useful are condensation products of fatty acids and polyethylene glycols,

wherein R is a long chain alkyl group having from 12 to 18 carbon atoms inclusive and x is an integer from 8 to 40 inclusive; polyoxyethylene derivatives of hexitol anhydride of sorbitol fatty acid esters such as Tween 80; polyoxyethylene ethers RO(CH CH O) CH CH OH wherein R is an alkyl group having from 6 to 18 carbon atoms and x is an integer from 4 to 40 inclusive. A commercial product which is an example of this group is Brij 30 in which R is lauryl and x is believed to be 10. There may also be used anionics x surface active agents such as highly sulfated fatty acid esters, e.g. lauryl sulfate (Tetranols) and alkyl aryl sulfoantes, e.g. dodecylbenzene sodium sulfonate, keryl benzene sodium sulfonate (Nacconol NRSF) and cationics such as quaternary ammonium compounds (Sapamine KW, Ethoquad 18/12). The amount of dispersing agent may vary broadly as from 0.01 to 50 percent. Generally, the dispersing agent is inert with respect to the ester and volatile during subsequent treating steps. The treating bath may also contain other agents useful for the treatment of the fiber as antistatic material, plasticizer and the like.

After impregnation of the fiber is accomplished, the excess volatile liquid is removed by any suitable method, as by squeezing out the excess by passing the fiber through nip rolls. It has been found very advantageous that there be retained by the treated fiber from 0.25% to 3% and more preferably from 0.75% to 2% by weight of ester. After removal of excess water the fiber is dried. Drying may be accomplished by heating at a temperature as in the range of 100 to about 200 F. for a time sufficient to dry the fiber. The drying step may be performed as a separate step or together with and apart from the crimping stage from the fiber. The impregnation from the fiber is performed at any suitable time during its processing. For instance, the ester may be included in the quenching bath when the fibers are subjected to such a step. This is a particularly convenient stage at which to treat a glass fiber. Or, for instance, the fibers may be treated by passing through the bath just prior to crimping, as may be done with polyamides, polyacrylics, polyolefins, or polyesters, for example, and copolymers thereof.

Suitable crimping techniques whereby the fiber may be crimped are shown in United States Patents 3,111,740, 2,972,798 (and others disclosed therein), 3,027,619, 3,037,260, and 3,090,096.

The impregnation of the fiber is preferably carried out by passing the fiber through a bath. If desired, however, the fibers may be treated with the solution or dispersion of the fatty acid ester by wetting the fiber by another suitable method such as by passing the fiber under a shower of a liquid finishing composition comprising the fatty acid ester. Or, the fiber may be passed across a wick which picks up the lubricant from a reservoir by capillary action. Moreover, the fiber need not be in a continuous form. For example, multifilament may be cut into staple fibers, and a blanket of the fibers may be carried on a fiat conveyor whereon the fibers may be sprayed with the liquid finishing composition comprising the ester of the invention.

The process of this invention is applicable to a wide variety of man-made fibers, particularly thermoplastic fibers made of synthetic polymers. As examples of fiberforrning synthetic polymers which may be used are the following polyolefins such as polyethylene, polypropylene; polyurethanes, polyvinyls such as polyvinylesters; polyacrylics, as acrylonitrile, and copolymers (e.g. those disclosed in United States Patent 2,960,752). Linear polyesters of aromatic dicarboxylic acids and dihydric compounds, such as polyethylene terephthalate; linear polycarbonamides such as, for example, polyhexamethylene adipamide, polyhexamethylene sebacamide, polymeric monoamino-monocarboxylie acids, such as polymeric 6- amino caproic acid; linear polycarbonates and other fiberforming thermoplastic polymers. Mixtures of such fiberforming synthetic polymers also can be used. The process of this invention is applicable particularly for the treatment of yarn generically referred to as nylon, including nylon 66, nylon 4, nylon 6, nylon 610, nylon 7, nylon 11, and their fiber-forming copolymers thereof, e.g. 6/66, 6/610/ 66, 66/610, etc. The lubricant of the invention is also useful to treat glass fibers.

In accordance with this invention there are produced potentially or latently crimpable fibers, filaments, or yarn, which can be readily changed into bulked, highly crimped stretchable product, particularly continuous filament yarn. The fibers may be crimped in accordance with any of the known methods for crimping textile strands and in particular because of the advantages discussed above, with the stuffer-crimping technique. The treated fiber may be a dyed or a virgin fiber. In accordance with the stuifercrimping technique of United States Patent 3,111,740 (mentioned above) for example, a textile strand is treated by heating the strand to soften the thermoplastic component, forcing the heated strand into and through a region from which exit of the strand is impeded sufiiciently to impart a crimped configuration thereto, and cooling the strand as soon as it assumes the crimped configuration. This is accomplished in an apparatus comprising means for forwarding a strand through a heating zone and into a cooling zone contiguous with the heating zone, means for heating the strand being forwarded through the heating zone, means for cooling the strand throughout the cooling zone, and a stuifer-crimper having a stufiing chamber with its entrance juxtaposed to the boundary between the heating and cooling zones to receive the strand from the heating zone. Prior to stuffer-crimping the fiber may be heated to within the range of ab0ut 350 F. for a time sufi'icient to soften the fiber.

The following examples in which parts and percent ages are given by weight, unless otherwise indicated, illustrate the preferred method of carrying out the treatment in accordance with the invention. The invention is not to be limited by the following examples.

Example 1 A tow of nylon filaments is forwarded through a suitable tank containing an aqueous dispersion of 2% of isooctyl palmitate. The bath is heated at a temperature of 140 F. The tow is passed through and out of the bath onto a pair of counter-rotating nip rolls which squeeze out excess water. The resulting fiber is then heated at 300 F. till dry.

The uncrimped strand is fed through the bore of an infeed guide and injected into the nip of counter-rotating rolls, which stuff the strand into the entrance of a jacketed stufling chamber as disclosed in United States Patent 3,111,740. The strand is heated by contact with the rolls and crimped by the rapid columnar collapse of the strand accumulating below the back-pressure gear, which penetrates the chamber from the back. Upon sufiicient accumulation of the strand to rotate the back-pressure gear against the frictional retardation imparted to it by slippage of the attached pulley against the belt in contact with it, the strand accumulation proceeds upward into the chamber proper, which is cooled by circulation of cooling fluid inside the jacket. Water ordinarily is suitable as the cooling fluid and is injected through inlet tubes near the base of the jacket and against deflecting fins which assure circulation of the water to the chamber wall in the vicinity of the entrance. The water circulates about the chamber within the jacket in contact with the helical circulating fins and emerges through the outlet tubes near the top of the jacket. The heated strand begins to cool immediately upon its entrance into the chamber and continues to do so as it passes upward in the chamber, finally approximating the temperature of the water in the jacket. The strand so processed remains lubricated throughout the entire operation.

Example 2 The procedure of Example 1 is repeated, adding to the bath polyoxyethylene ether of cetylalcohol to give a 5% concentration. A fiber of equally satisfactory properties is obtained when crimped by identical stutter-crimping, such as disclosed in United States Patent 3,111,740. In another modification, the lubricated fiber is directed directly from the treating bath to the stuffing-crimping chamber.

Examples 39 The procedure of example is repeated with the following modifications:

(3) Replacing the isooctyl palmitate by 3% of butoxy ethyl stearate.

(4) Replacing the isooctyl palmitate by 3.5% of isodecyl palmitate.

(5) Replacing the isooctyl palmitate by 4% isooctyl stearate.

(6) Using with the lubricant, a polyoxyethylene alkyl phenol.

(7) Replacing the polyhexamethylene adipamide with a polyethylene terephthalate fiber.

(8) Using 1.8% glycerol tri-stearate in a 1% dispersion of a polyoxyethylene ether of cetyl alcohol.

(9) Feeding the fiber directly from the stutter-crimping apparatus.

Each fiber of the above examples, when exposed to a temperature of 400 F. for five minutes, retains its coating and remains satisfactorily lubricated.

Each fiber is crimped by passing through a stuifercrimper. The temperature in the stufler box is above 320 F. A highly satisfactory crimped yarn is obtained. By substitution of other lubricants of the invention, highly lubricated yarns and fibers with a coating highly ther mally stable are obtained. One skilled in the art may without ditficulty vary the conditions to perform under conditions most suitable to achieving his particular purposes.

We claim:

1. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of an alkyl ester of a saturated fatty acid of 16 to 22 carbon atoms, the ester having an alkyl group of 6 to 12 carbon atoms, removing excess water from the fiber, and stuffer-crimping the fiber coated with the fatty acid ester in a stuifercrimper chamber without decomposition of the coating.

2. The process of claim 1 in which the alkyl group of the ester is branched.

3. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of an ether of a saturated fatty acid of 16 to 22 carbon atoms, the ether having an alkoxy group of 4 to 8 carbon atoms, removing excess water from the fiber and stuifer-crimping the fiber coated with the fatty acid ether in a stuifer-crimper chamber without decomposition of the coating.

4. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of isooctyl palmitate, removing excess water from the fiber and stufier-crimping the fiber coated with the fatty acid ester in a stuifercrimper chamber without decomposition of the coating.

5. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of butoxy ethyl stearate, removing excess water from the fiber and stutfercrimping the fiber coated with the fatty acid ester in a stuffer-crimper chamber without decomposition of the coating.

6. A process which comprises impregnating a synthetic fi'ber with an aqueou dispersion of an alkyl ester of a saturated fatty acid of 16 to 22 carbon atoms, the ester having an alkyl group of 6 to 12 carbon atoms, and a dispersing agent, removing excess water from the fiber and stuifer-crimping the fiber coated with the fatty acid ester in a stuifer-crimper chamber without decomposition of the coating.

7. The process of claim 6 in which the dispersing agent is the polyoxyethylene ether of cetyl alcohol.

8. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of an alkyl ester of a saturated fatty acid of 16 to 22 carbon atoms, the ester having an alkyl group of 6 to 12 carbon atoms, removing excess water from the fiber and stuifer-crimping the fiber coated with the fatty acid ester in a stuifer-crimper chamber at a temperature in the range of 300 to about 400 F. without decomposition of the coating.

9. A process which comprises impregnating a synthetic fiber with an aqueous dispersion of an alkyl ester of a saturated fatty acid of 16 to 22 carbon atoms, the ester having an alkyl group of 6 to 12 carbon atoms, drying the impregnated fiber, and stutter-crimping the dried, impregnated fiber at a temperature below the decomposition temperature of the ester.

10. The process of claim 9 wherein the fiber is a thermoplastic synthetic polymer.

11. The process of claim 9 wherein the ester is butoxy ethyl stearate.

12. The process of claim 9 wherein the ester is isooctyl stearate.

13. The process of claim 9 wherein the ester is isodecyl palmitate.

References Cited UNITED STATES PATENTS 2,069,303 2/ 1937 Dreyfus et al.

2,282,568 5/ 1942 Finzel.

2,960,752 11/ 1960 Sonnino 28-76 3,235,442 2/1966 Stump 16l173 2,207,696 7/1940 Robinson et al. 117138.8 X 2,406,542 8/1946 Howorth et al. 117-1395 2,436,978 3/ 1948 Standley et al. 117-1395 X 3,193,407 7/1965 Keller et al. 117-138.8

WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner.

US. Cl. X.R. 

